Conventionally, a mixer of a type in which magnetized stirring rotator is arranged at the bottom of a container accommodating liquid, and the stirring rotator is rotated by the rotatably driven magnet to stir the liquid is known for stirring the micro-fluid and so on (see e.g., patent document 1). However, such conventional mixer of the type driven by magnets will become impossible to use since the dimension of the microscopic flow path of an integrated chemical analysis equipment (micro-analysis chip) for mixing and reacting a very small amount of test solution and reagent to perform analysis is assumed to have a width of a few dozen μm and a depth of a few dozen μm in the future.
Therefore, research and development of a mixer of micro-fluid using micro-machining has been actively performed, and two methods of (1) a method of enhancing the mixing efficiency by converting the two liquids (test solution and reagent) to be mixed to a multi-layered flow by devising the number and shape of flow inlets, (2) a method of forming a groove in a flow path wall surface and generating turbulent flow, and (3) a method of vibrating a diaphragm (thin film) with PZT (lead zirconium titanate) and mixing the microscopic fluid thereon are mainly proposed. Comparing the three methods, the active method (3) more efficiently mixes the two liquids compared to the passive methods (1) and (2), but the two liquids may not necessarily be mixed at satisfactory efficiency since none of the methods regards directly stirring the two liquids.
In view of such aspect, a light pressure rotator has been proposed by the inventors of the present invention for directly mixing the micro-fluid (see patent document 2). The light pressure rotator disclosed in patent document 2 is a rotator being trapped by a so-called light pressure generated, when the change in momentum in refraction and reflection of light such as laser light is transformed as dynamic momentum to the microscopic object having light transmissivity, in a direction perpendicular to the surface thereof, and being light pressure rotated with the central axis of rotation as the center. The light pressure rotator is expected to be applied to optical micro-motor, optical micro-drill and the like, and can be used as an optical mixer for stirring the surrounding medium in time of light pressure rotation by arranging a plurality of blades on the side of the central axis of rotation.    Patent document 1: Japanese Laid-Open Patent Publication No. 10-192680    Patent document 2: Japanese Patent No. 3364780